It is generally desirable to design portable and stand alone electrical apparatus so that they are more efficient than electrical apparatus that is for example connected to a national electrical distribution network.
One approach that has been adopted, for example in Bluetooth devices, is to have apparatus with different modes. For example an apparatus may have a low power consumption sleep mode and also a high power consumption operational mode. Such apparatus typically remain in the sleep mode until some action is required which requires the apparatus to enter the operational mode.
When an apparatus is in an operational mode its power consumption is significantly greater than when it is in a sleep mode. The overall power consumption of an apparatus can therefore be most effectively reduced by improving the efficiencies of the operational mode of the apparatus.
The inventors have additionally recognized that significant advantages may also be obtained by improving the power consumption efficiencies of the sleep mode.